1. Field of the Invention
The invention relates to an adjustable-length column for chairs, tables or the like comprising an upright tube and a pneumatic or hydropneumatic length-adjusting element arranged therein concentrically of a common central longitudinal axis, the housing of which element is radially supported in a guide of the upright tube and displaceably guided in the direction of the axis, and the piston rod of which element is arrested, in the vicinity of its free end, on a bottom plate of the upright tube in the direction of the axis, the housing being guided, by means of a non circular-cylindrical and non-circular cross-section, displaceably in the direction of the axis in a recess suited in cross-section.
2. Background Art
An adjustable-length column of the generic type is known in which the housing of the gas spring serving as a length adjusting element has a non-circular, as a rule hexagon cross-section. The recess, serving for guiding, of the guide bushing has a corresponding cross-section. This configuration is extraordinarily difficult to produce and, moreover, has the disadvantage of the housing tilting in the guide bushing for comparatively strong twisting strain so that impeccable axial displacement is no longer possible.